stabilize varnishstat curses mode test

Could be that there is the bereq # printed right next to the client |
as in this vtest result:

**   top  === process p1 -expect-text 22 0 { | }
**** dT   3.593
**** v1   vsl|          0 CLI             - Rd ping
**** v1   vsl|          0 CLI             - Wr 200 19 PONG 1585796425 1.0
**** dT   3.806
**** p1   stdout|\x1b[1;10H2\x1b[22;24H|#

bin/varnishtest/tests/u00009.vtc

@@ -34,7 +34,7 @@ client c1 {
 
 varnish v1 -vsl_catchup
 
-process p1 -expect-text 22 0 { | }
+process p1 -expect-text 22 0 { |}
 
 process p1 -expect-text 3 1 {20_}